Athletic shoes are used in a wide array of settings, from casual lifestyle wear to performance wear in athletic activities including, but not limited to: recreational walking, running, cross-training, football, soccer, basketball, tennis, lacrosse, rugby, cross-country, volleyball, running, racquetball, squash, handball and track and field. The athletic shoe segment of the footwear industry encompasses cleated and non-cleated shoes made from a variety of materials including, for example: rubber, plastics, leather, synthetics, composites, woven and non-woven fabrics, foams, gels, and the like—all designed for athletic use or in an athletic style. In general, shoe producers strive to improve the comfort, athletic performance and style of athletic footwear. In addition to social custom, athletic shoes are worn to provide protection to the foot while concurrently providing a competitive advantage by incorporating innovation and performance based technologies specifically tailored for task, terrain and function.
There have been a myriad of various technologies and methodologies that have propelled athletic shoes to their modern day presentations. While many of these developments have made improvements by reducing the weight of the shoe, there have also been advancements directed to its performance and comfort. In face of these improvements, modern athletic shoes still employ insufficient toebox designs that are restrictive and cause agitation to the toes during certain athletic maneuvers or movements, leading to discomfort and injury. Many athletes prefer to wear tight fitting shoes to gain greater control or to garner a better “feel”. Unfortunately, in addition to wearing athletic shoe designs that employ insufficient toeboxes, wearing ill-fitting shoes further contributes to and places an individual at a greater risk for incurring a number of painful and sometimes debilitating injuries. Risk of injury in field sports has further increased with the advent of artificial turf fields and pliable athletic shoe designs, which contribute to the application of higher peak pressure forces to the foot and hallux during athletic performance. This has resulted in a significant increase of foot/toe injuries for athletes in various diverse sports.
There are a number of foot injuries that have plagued athletes, caused wholly or in part to interaction or movement of the foot within the shoe when worn by the athlete for its intended purpose. Such injuries are particularly prevalent where the foot or toes repeatedly impact or forcibly engage the toebox of the shoe during abrupt athletic footwork movements such as stopping, changing direction or cutting, and due to the use of tight or improperly fitting shoes.
One serious injury that may result from an inadequate toebox or ill-fitting shoe is referred to as “turf toe”. The term “turf toe” is commonly used to refer to any serious injury to the hallux (big toe). Turf toe is often somewhat an ambiguous medical diagnosis, since as many toe injuries that appear similar in presentation to turf toe are inaccurately deemed as turf toe. The correct epidemiological definition of turf toe is a sprain of the first metatarsophalangeal joint (“MPJ” or “MTP joint”). The MPJ is the joint located at the base of the big toe and is used in pushing off with the foot. Damage to this joint occurs when the MPJ is jammed or hyperextended. Symptoms include: swelling, bruising, loss of range of motion, severe pain and sometimes an inability to bear weight. Turf toe most frequently occurs in athletes who compete on grass or turf playing surfaces when a player lands on the back lower leg of another player who has his/her foot plantar flexed at the angle with the big toe extended. Turf toe can also occur as an impaction injury where the proximal phalanx dorsally jams into the metatarsal head. Such impaction may transpire as a result of a direct blow to the big toe from another player or from a collision of the big toe against the shoe's restrictive toebox. Prolonged use of forefoot-limiting shoes and insoles places one at risk for an increased occurrence of turf toe. Turf toe is a debilitating injury and is often described by patients as being extremely painful and can keep athletes from returning to competition for significant periods of time. It commonly takes from two to six weeks for a turf toe injury to heal to a status such that one can return to a normal functioning level, and generally leaves the affected individual more susceptible to repeat injury. An external view of an inflamed MPJ turf toe injury is illustrated in FIG. 1.
Another common injury that often results from wearing a shoe with an inadequate toebox or improper shoe size is subungual hematoma, often referred to as “runner's toe”, “jogger's toe”, “tennis toe” or “soccer toe”. Subungual hematoma is the collection of blood underneath a toenail, as illustrated in FIG. 2. For distance runners and joggers, subungual hematoma is often caused by the repetitive thrusting of the hallux against the toebox. The friction generated between the toebox and toenail contributes to nail plate separation from the nail bed, which leads to bleeding and pooling of blood. This in turn causes pressure buildup and tissue damage under the toenail. Subungual hematoma is also referred to as “black toenail” since it frequently results in a red/purple-black discoloration of the toenail, a common precursor to the nail itself falling off completely. Subungual hematoma is not only expressed in runners, but is also a common injury for athletes wearing cleated and non-cleated shoes during sport competitions such as football, soccer, lacrosse, rugby, racquetball, squash, tennis, volleyball and basketball—to name a few. During competition, athletes must frequently change direction, jump or come to a sudden stop by way of planting the foot in or on the playing surface. In planting one's foot to run, stop, jump, cut or change direction, the shoe is often momentarily fixed in or to the ground for a time causing the foot and toes to thrust or slide forward within the shoe, thus often abruptly engaging the inner toebox portion of the shoe. Such impact of the toes against the toebox is a likely suspect for subungual hematoma. While the injury does not generally require surgical intervention, it is common for athletes with subungual hematoma to have a physician or athletic trainer perform trephination procedures in an attempt to alleviate pressure buildup beneath the toenail. Subungual hematoma can greatly affect one's athletic performance or even inhibit one from staying active while playing altogether, as it is an extremely painful injury due to tissue damage and intense buildup of pressure under the nail.
Sesamoiditis is another common foot ailment that can be caused from forefoot limiting shoes. The sesamoids are two small bones about the size of jelly beans located in each foot between the first metatarsal bone and the phalanx of the big toe. The sesamoids act as the fulcrum in the foot's important pulley system, assisting the flexor tendons in the flexion of the big toe as well as augmenting the tendons' ability to bear weight (see FIG. 3). Sesamoiditis is defined as the inflammation of the sesamoid bones. Sesamoiditis is most commonly caused by either repetitive and/or exhaustive stress placement on the sesamoid bones during plantar flexion. “Jamming” of the phalanx and first metatarsal bone caused, for example, by repeated sudden impact of the hallux against the toebox of a shoe, may also incite Sesamoiditis. Sesamoiditis is a common form of tendonitis that is very aggravating, not only because of the pain experienced, but also because it is not easily cured.
Hammertoe or mallet toe are deformities to the toes that are caused by tight fitting shoes in the toebox region, or by shoes with raised heels. Such deformities are particularly of concern to athletes who choose to wear tight fitting shoes to minimize slippage or sliding of the foot within the shoe when stopping, cutting or changing direction during an athletic maneuver. Hammertoe or mallet toe can be characterized as the shortening and stiffening of the toe's tendons, fixating them in an upward bend at the middle joint of the toe, followed by a downward bend at the head of the toe (see FIG. 4). This results in a toe orientation that resembles that of a hammer-like or claw-like curled shape. Hammertoe can inflict painful corns or calluses simply by wearing shoes since the unnatural bending of the toes may rub or jam against the shoe. As time progresses, the toes will eventually become permanently fixed in the “hammertoe” curled position, at which point surgical intervention may be needed in order to alleviate pain, restore proper flexibility, and appease aesthetic appearance.
Ingrown toenails may be induced by a countless number of things, but improper nail trimming and ill-fitting shoes are the most common causes. An ingrown toenail is the encroachment growth along the side or edge of the toenail into the surrounding soft tissue or skin of the toe (see FIG. 5). This injury is caused when extra pressure is placed on the toe which is most frequently exacerbated by poorly fitting shoes. Ingrown toenails are indicated by pain, swelling, redness and infection.
The foot and toe injuries outlined above are often caused and intensified by forefoot/hallux limiting, tight fitting shoes. The present invention addresses such foot injuries by providing a more strategic toebox construction that disperses peak pressure placement on the foot/hallux for reducing toe jamming forces that contribute to such injuries.
A number of techniques and devices have been tried in the past to address the prevention, minimization or treatment of the above injuries associated with athletic shoes. One technique has been to simply tape toes together in an effort to distribute the impact forces from the toebox so that a single toe (e.g., the hallux or big toe) does not receive the entire impact force. Other approaches for treating those already affected with turf toe injuries include the use of inserts such as insole inserts for insertion within or as a part of the athletic shoe (U.S. Patent Publication 2012/0240431) and toe brace/splint structures (U.S. Patent Publication 2006/0226737) for immobilizing or restricting movement of the MPJ to reduce pain during rehabilitation. Such devices address post-injury conditions, but do not address reduction or elimination of the causes of turf toe injuries.
A number of athletic shoe innovations have been directed toward restricting forward movement of the foot within the shoe. Some of such innovations have been directed to lacing arrangements and the use of stabilizing members such as reinforcing strips for limiting foot movement. U.S. Pat. No. 3,138,880 is an example of such an arrangement wherein each lacing eyelet ring is connected to a narrow reinforcing strip that extends down the side of the shoe to the margin of the upper. U.S. Pat. No. 4,255,876 discloses an athletic shoe that uses a limited number of reinforcing strips that are not directly associated with each of the lacing eyes. This patent discloses a single reinforcing member surrounding the tongue opening of the upper in zigzag fashion with lacing holes formed therein in like fashion so that alternating pairs of wide set and narrow set holes are disposed along the tongue length. U.S. Pat. Nos. 4,413,431 and 4,813,158 describe yet other variations of lacing eyelets containing reinforcement portions and medial and lateral reinforcement portions. Such innovations reduce, but do not prevent movement of the foot toward the toebox of the shoe.
Another approach that departs from conventional athletic shoe design is a configuration referred to as a “minimalist shoe” configuration. Such shoes have gained popularity in the cross-training and running sports. Minimalist shoes do not employ the traditional toebox portion of an athletic shoe, but are configured as slim outlines of the foot itself, with individual receptor slots for each of the toes. These shoes purportedly provide the wearer with the closest footwear option to that of wearing no shoes at all. The popularity surrounding minimalist shoes is largely due to the fact that they capitalize on delivering shoes that offer a desired barefoot sensation and are lightweight. Vibram S.p.A. markets minimalist shoes (FIG. 6) under its FiveFingers™ brand and claims that such shoes influence runners into a more natural running gait, thereby lowering the impact forces on one's body. However, recent studies have concluded that such shoes are not biomechanically fit for everyone and have found that half of the test subjects did not adjust their running form when making the switch to minimalist shoes and as a result, experienced high impact forces that were nearly twice as high as those that would occur when wearing athletic shoes of traditional design.1 Parker-Pope, Tura. “Are Barefoot Shoes Really Better?” The New York Times. NY Times.com. 30 Sep. 2011. Web.
One practice or method that athletic shoe wearers have utilized as an injury prevention measure and as a mechanism to improve the comfort of the more conventionally configured athletic shoes is to personally alter the toebox by making a cut through the toebox material in the vicinity of the big toe, usually in the shape of an “X”. Cutting of the toebox provides more room for the big toe, and enables the big toe to move forward into the cut region through and beyond the front face of the toebox, reducing toe jamming and lowering the pressure placed on the foot and toe joints when running, jumping or cutting to change directions. Athletes employing such technique claim to like the open, breathable feel that such cuts provide. Some such practitioners also contend that the cuts make their shoes feel lighter and mimic the feeling of running barefoot. Such personal altering of the toebox has been especially prevalent in the sport of football. While making such personal alteration cuts to the toebox of manufactured athletic shoes may in fact improve the comfortability and toe jamming relief of the shoe, no covering material has been incorporated over the cuts, leaving the toes and interior of the shoe directly exposed to the external environment. Accordingly, undesirable objects such as rocks, sand, dirt, grass, field turf beads, and other miscellaneous foreign objects and debris are able to loosely infiltrate the shoe, causing discomfort and even injury to the wearer. Other problems associated with shoes having self-made cuts formed therein is that the hand made cuts are not necessarily optimally placed for alignment with the big toe as it moves within the shoe, and there are no control mechanisms provided to reclose the cut opening when the foot slides back toward the rear of the shoe or to prevent the cuts from increasing in size and growing too large leading to premature breakdown of the toebox and reduction of the integrity of the toebox.
Besides injury prevention and performance, comfort is an important priority for shoe producers and consumers. There have been a plethora of technologies and choice materials used in the design and creation of more comfortable shoes; however, there is always room for improvement in the comfort of athletic shoes. One such way of enhancing comfortability of an athletic shoe is through a significant ventilation system that aids in the breathability of the shoe. The materials selected for the body of the shoe often comprise lightweight wafer or mesh-like breathable fabric that allows for a certain degree of air circulation. In general, however, the toebox portion of athletic shoes, and particularly those with restrictive tight fitting toeboxes have not been particularly susceptible to designs for improving ventilation within the toebox. This has particularly been true for athletic shoes used in contact sports such as football. Those techniques that have addressed the ventilation comfort issue have revolved primarily around changes made to the upper material, or to contour adjustments made to the toebox.
There are some athletic shoes on the market that employ lightweight mesh-like material in the toebox area that promotes ventilation. One such biking shoe is the SHR-300 Road Cycling Shoe sold by Shimano, Inc., that has two breathable mesh cutouts on either side of the toebox for ventilation purposes (see FIG. 7). The mesh, however, does not possess any unique stretchability properties that allows for any expansion of the toebox, and such shoe can only be practically used for biking purposes due to its pedal cleats and hard exterior shape which do not readily allow such shoe to be used for recreational use or casual wear.
The present invention addresses the deficiencies and shortcomings associated with prior known athletic shoe design techniques for minimizing and reducing possible foot and toe injuries associated with impact forces and pressures applied through the shoe toebox to the toes and feet of the person wearing the shoes.